C++ Problem declaring multiple object instances on the same line
For a homework assignment, I'm having a hard time understanding the behavior when the main class is instantiating two objects of the same class on the same line as follows. Note that the object of the assignment is for the class to behave like an int:
main () {
MyClass x,y = 5;
cout << "x = " << x << endl; // outputs x = 0...why not 5???
cout << "y = " << y << endl; // outputs y = 5
}
and here's header file class definition:
class MyClass {
public:
MyClass(int initValue = 0); //constructor
operator int() {return myValue}; //conversi开发者_StackOverflow中文版on operator to int
private:
int myValue;
}
and finally, my source file:
#include "MyClass.h"
MyClass::MyClass(int initValue) {
myValue = initValue;
}
Why doesn't x get initialized with the value of 5 like y does?
The problem is that C++ is parsing
MyClass x,y = 5;
As if you had written
MyClass x;
MyClass y = 5;
And so x
is getting default-initialized rather than initialized with 5. To fix this, change the line to read
MyClass x = 5, y = 5;
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